The plan was submitted by Tokyo Electric Power Company Holdings in December based on the government’s decision last year to discharge sewage as a necessary step for the ongoing cleanup and dismantling of the plant.
A massive earthquake and tsunami in 2011 destroyed the cooling systems at the Fukushima power plant, causing three reactors to melt down and release large amounts of radiation. The water that was used to cool the three damaged reactor cores, which remain highly radioactive, has since leaked but has been collected and stored in tanks.
The community and neighboring countries are still concerned about the potential health risks of discharging sewage containing tritium – a by-product of nuclear power generation and a possible carcinogen at high levels.
The government and TEPCO say more than 60 isotopes selected for processing can be lowered to meet safety standards, with the exception of tritium, but is safe if diluted. Scientists say the impact of long-term, low-dose exposure on the environment and humans is unknown, and that tritium may have a greater impact on humans when consumed in fish than in the water.
Japan’s nuclear authority chairman Toyoshi Fuketa said the plan is being carefully crafted so that the impact of radiation on the environment can be even below the legal limit in the event of imaginable risks.
Under the plan, TEPCO will transport water that has been treated below discharge levels via a pipeline from the reservoirs to an onshore facility, where the water is diluted with seawater.
From there, the water will enter an underwater tunnel to be discharged about 1 kilometer (0.6 mile) from the plant to ensure safety and minimize the impact on local fisheries and the environment, according to TEPCO. .
The plan will become official after a 30-day public review, a formality that should not nullify approval.
The green light came just as International Atomic Energy Agency Director Mariano Grossi arrived in Japan for meetings with senior officials to discuss the plan, which has garnered international attention.
Fuketa will meet Grossi on Friday after the IAEA director’s visit to the Fukushima plant on Thursday and meetings with other Japanese officials.
The government and TEPCO plan to start gradually releasing the treated water in spring 2023.
The contaminated water is stored in about 1,000 tanks at the damaged plant, which officials say must be removed so that facilities can be built for its dismantling. The tanks are expected to reach capacity of 1.37 million tonnes next year – slower than an earlier estimate from later this year.
Japan has asked for help from the IAEA to ensure the release of the water meets international safety standards and to reassure local fishermen and other communities as well as neighboring countries who have strongly criticized the plan. .
A team of IAEA experts visited the plant in February and March for meetings with the Japanese government and TEPCO officials. The task force, in a report released in late April, said Japan was making “significant progress” on the plan and taking appropriate steps towards the planned discharge.